Abstract: The theoretical analysis of the stress concentration factor K of three types of tubes with three different types of unfused defects is very complicated. In this paper, the finite element numerical analysis software is used to be established the finite element model of the three⁃way pipe with defects under the action of internal pressure. After calculation, the stress concentration factor K and its variation law under the four influencing factors are obtained. The results show that the stress concentration factor K of the three⁃way tube with three different unfused defects is relatively large in the shoulder and collar region, and the stress concentration is serious. The stress concentration factor K increased slowly with the increase of the axial length and depth of the defect, and decreased rapidly with the increase of the circumferential length of the defect.

Key words: Unfused defects, Stress concentration factor, Finite element analysis, Three?way pipe, Stress

摘要： 含三类不同未熔合缺陷的三通管件应力集中系数K的理论解析十分复杂。因此，采用有限元数值分析软件，建立在内压载荷作用下含所研究缺陷三通管的有限元模型，经过计算得出4个影响因素下的应力集中系数K及其变化规律。结果表明，含三类不同未熔合缺陷的三通管在肩部及领口区域应力集中系数K相对较大，且应力集中现象严重，应力集中系数K随缺陷的轴向长度、深度的增加而缓慢增大，随缺陷环向长度的增大而迅速减小。

关键词: 未熔合缺陷, 　应力集中系数, 　有限元分析, 　三通管, 　应力